1. Technical Field
The present invention relates to a circuit board for mounting electrical circuits such as power supply circuits, and an electrical connection box containing the circuit board.
2. Related Art
In general, when a circuit board including electrical circuits such as power supply circuits is mounted on the vehicles, the circuit board is accommodated in a box. In this case, when the circuit board is a circuit board including a large-current electrical circuit such as a power supply circuit having a large calorific value, the radiation performance of the box should be enough large.
As a countermeasure for radiating the heat produced from the electrical circuits, as shown in FIG. 6, there is known in the art a circuit board that a radiator plate 2 formed of a metal plate is superimposed on a board 1 and an electrical component 3 is connected to an exposed portion of the radiator plate 2 so as to transmit the heat from the electrical component 3 to the radiator plate 2 (for example, see JP-A-11-163476).
However, in the circuit board, circuits cannot be disposed on the surface to which the radiator plate 2 of board 1 is attached. Furthermore, since the radiator plate 2 is exposed, the mountable area is limited. As a result, in order to secure the necessary mountable area, the board increases in size. Accordingly, when the circuit board is contained in an electrical connection box, the electrical connection box also increases in size.
In addition, since the radiator plate 2 that is a different member from the board 1 is bonded, the number of components and the number of process steps are increased, and then the cost is raised. Further, at the time of disassembling the electrical connection box containing the circuit board, the radiator plate 2 should be detached from the board 1, which requires a much effort for the disassembling.